1. Field
Embodiments described herein relate generally to a transmission technique of copying digital data between devices.
2. Related Art
As publicly known, the way in which audiovisual (AV) contents formed of digital data are used has recently changed, as computer networks, such as broadband and local area networks (LANs), become prevalent. A user can enjoy contents on a rental model, in which a content that the user has rented for a certain period of time via a network has to be returned or cannot be used after the certain period of time has elapsed, as well as on a model that permanently owns contents that the user has purchased via a network. Contents in a rental model are restricted in terms of the time during which the contents can be viewed after viewing is started.
The contents have an advantage of being easily copied without being deteriorated. On the other hand, the contents must be treated with care with respect to their copyrights. That is, the management method is important when the contents are handled on a rental model.
Jpn. Pat. Appln. KOKAI Publication No. 2004-5939 discloses a playback device configured to play back a content based on information on permitted playback time included in copyright information until the remaining time becomes zero, and does not play back when the remaining time becomes zero.